Project Description:

Project Description:

A bad start during early growth may have long-lasting consequences on an individual's later behaviour and performance. This may be counteracted by compensatory mechanisms, such as "catch-up" growth - given a chance, an individual can accelerate growth and re-gain the normal growth trajectory. However, this compensation appears to carry costs: recent studies have revealed impaired physiological function and reduced lifespan later in life. In this study, we had four main aims:

1) Modelling the optimality of state-dependent catch-up growth strategies under various ecological and evolutionary scenarios2) Quantifying the extent to which fish (green swordtails, Xiphophorus helleri) subjected to poor growth conditions from early in life a) show variation in state-dependent resource allocation and b) show compensatory growth if growth conditions subsequently improve3) We tested to what extent compensation and relative investment in body- and tail-growth varies with ontogenetic stage4) We tested the long-term consequences of poor vs. good vs. compensated growth conditions as juveniles on a) burst and sustained swimming performance, b) survival rates, c) dominance status/competitive ability, d) attractiveness to potential mates (males), e) fecundity and offspring quality (females; time permitting inter-generational effects will also be studied.